As for the crash bike...Once it got out of insurance limbo, I did what any tinkerer would do and started rebuilding it.
This corner of the cage took most of the impact:
All of the bars & tubes have bent, and the cage is pushed forward at least an inch. The rear battery mount isn't accessible anymore.
The ditch gravel did a number on this side:
Stock photo showing an un-bent cage:
The whole cage is a bit lop-sided now.
Those center tubes used to be vertical!
So the cage yielded and absorbed a bunch of the impact energy. It successfully kept all 4 of the riders from directly hitting the car. And that's just...amazing. When I first assembled the cage, I thought the entire bike was overbuilt. It weighs 70 pounds without the cage, it has too much tubing, the cage uses an obsessive number of bolts, etc. Looking at it now, I won't complain. That held up to a 40MPH collision much better than I would have dreamed. I have checked every (fully TIG-welded) weld on the aluminum frame and cage, and I have found no visible cracks. The cage is trash, and a number of non-structural items are broken. But the main frame is still straighter than several of my old commuter bikes. It's a strong vote of confidence in the frame's design & production quality that it held up so well. Especially coming from a cheap entry-level bike. They seem to have spent their money where it counts.
For comparison, here's a picture of the Kia that hit them:
Physics dictates that the bike riders always lose in a car-bike collision. But I'm confident that the bike itself held up better than the car did.